A method and a device of this kind are e.g. known in the art from WO 2007/012215 to the applicant of the present invention. This PCT application discloses the creation of so-called ripples by means of a femtosecond laser on a workpiece that may be provided with a hard material layer consisting of superhard amorphous carbon having a fraction of more than 50% of diamond-like sp3 bonds known under the designation ta-C, of tungsten carbide, WC, boron carbide, B4C, silicon carbide, SiC, or similar hard materials. As appears from different documents available in the Internet, mainly the superhard amorphous carbon films, ta-C, are very suitable for various applications, more particularly for tribological applications but also for optical diffraction applications.
Besides the application of laser devices having pulse durations in the femto- and picosecond range, it is also known per se to use excimer lasers having pulse durations in the nanosecond range and wavelengths in the ultraviolet range for microstructurings. A laser microstructuring of wear-resistant surfaces of solid bodies is mainly required for embossing rollers or dies when these embossing rollers or dies are e.g. intended for embossing fraud-resistant authentication features or particular optical diffraction attractive signs on packaging foils for cigarettes or foods. Such packaging foils are mostly made up of a paper or plastics layer provided with a vapor-deposited or sputtered metal layer, or they are entirely made of metal, mostly aluminum, or entirely of paper or plastics with a surface treatment that produces the optically and optical diffraction effective features and structures.